The process of leukocyte migration across the vascular endothelial barrier is fundamental to the process of inflammation and the response to infection. We will quantitate the effect of various medications such as topical corticosteroids, oral nonsteroidal anti-inflammatory drugs, and mast cell stabilizers in several of these processes. We have applied intravital microscopy in animal systems to visualize, quantitate and analyze this process. Recent advances in confocal microscopy have allowed a European group to quantitate leukocyte endothelial rolling and sticking in the microvasculature of the human eye. Combining our clinical expertise in confocal microscopy and our experience analyzing leukocyte vascular interactions, we propose to utilize in vivo confocal technology to quantitate leukocyte rolling and arrest in 4 different human vascular beds: the limbus, conjuctiva, episclera, and sclera. With these three specific aims: Aim one, we propose to image rolling and sticking of leukocytes in four different normal ocular vascular beds: the conjunctiva, limbus, episclera, and sclera. Aim two, we will compare leukocyte-endothelial dynamics in specific vascular beds in seven disease states: a) allergic seasonal conjunctivitis, b) Sjogren's syndrome and dry eye, c) blepharitis, d) graft versus host disease (GVHD), e) episcleritis, f) scleritis, and g) anterior uveitis. Aim three, we will determine the effect of medications including topical prednisolone acetate, a mast cell stabilizer (optipranolol), or an oral nonsteroidal anti-inflammatory drug (indomethacin) on endothelial-leukocyte dynamics in diseases for which each is frequently prescribed. Our studies will directly clarify the pathogenesis of several troublesome and rarely studied ocular disease processes. These studies will elucidate the mechanism by which medications alter these processes. Most importantly these studies will quantitate a fundamental human biological process in microvascular beds that have not previously been imaged. [unreadable] [unreadable]